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1.	Hang, Chang C., et al. (author) Practical Aspects of PID Auto-Tuners Based on Relay Feedback 1988 In: 2nd International IFAC Symposium on Adaptive Control of Chemical Processes 1988 (ADCHEM '88), Lyngby, Copenhagen, Denmark, 17-19 August. - 1474-6670. ; 21:7, s. 153-158 Conference paper (peer-reviewed)
2.	Johansson, Rolf (author) Lyapunov Design for Adaptive Control of Robots 1989 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - 1474-6670. ; 22:3 Journal article (peer-reviewed)abstract This paper presents algorithms for continuous-time direct adaptive control of robot manipulators. Lyapunov theory is used for controller design and stability investigation. Algorithms for rapid continuous-time adaptive control are presented.
3.	Källström, Claes, et al. (author) Adaptive Autopilots for Large Tankers 1978 In: 7th Triennial World Congress of the IFAC : A Link Between Science and Applications of Automatic Control, Helsinki, Finland, 12-16 June - A Link Between Science and Applications of Automatic Control, Helsinki, Finland, 12-16 June. - 1474-6670. ; 11:1, s. 477-484 Conference paper (peer-reviewed)abstract The adaptive autopilots are based on velocity scheduling, a self-tuning regulator for steady state course keeping, a high gain turning regulator with variable structure, and a Kalman filter. Results from simulations and full-scale experiments on three different tankers are presented. The autopilots are shown to work excellently under different loads, speed and weather conditions.
4.	Olsson, Gustaf, et al. (author) Estimation and Control of Biological Activity in the Activated Sludge Process Using Dissolved Oxygen Measurements 1977 In: IFAC Symposium on Environmental Systems Planning, Design and Control, Kyoto, Japan, 1-5 August. - 1474-6670. ; 10:7, s. 745-755 Conference paper (peer-reviewed)abstract The control of an activated sludge process is considered. It is discussed how the organism activity is a crucial information for the control. It is shown, how the concentration profile of dissolved oxygen (DO) in the biological reactor is related to the sludge activity. As a result the DO profile is a useful measurement information for control purposes
5.	Åström, Karl Johan, et al. (author) Analysis of a Scheme for Iterated Identification and Control 1994 In: IFAC Symposium on System Identification (SYSID'94), Copenhagen, Denmark, 4-6 July. - 1474-6670. ; 27:8, s. 473-478 Conference paper (peer-reviewed)abstract This paper presents analysis of a scheme for iterated identification and control design. The approach is based on least squares identification in closed loop and pole placement design. It has previously been shown that the criteria for control and identification are the same provided that the data filters are chosen properly. The iterated scheme may be viewed as a recursion in model parameters. Each step consists of system identification and control design. Interesting questions are then: What are the fix points? Are the fix points stable? These questions are investigated for some simple examples. Relations to other problems like model reduction and adaptive control are also discussed.
6.	Birk, Wolfgang, et al. (author) Foam level control in a water model of the LD converter process 2001 In: Automation in mining, mineral, and metal processing 2001. - Oxford : Published for the International Federation of Automatic Control by Pergamon. - 1474-6670. - 0080436927 Conference paper (peer-reviewed)abstract This paper deals with estimation and control of foam level in dynamic foaming. An improved foam level estimation methodology from a microphone signal and its automatic calibration is presented. The dynamical reaction of the foam level on air lance movements is modelled using system identification. Based on the resulting mathematical model, a controller for foam level stabilisation is designed and applied to a water model, representing the LD converter process. It is shown that the foam level can be controlled using a microphone as the measurement device and air lance movement as the actuator.
7.	Ding, Limei, et al. (author) Application of fuzzy control to a flotation process 1999 In: Elsevier IFAC Publications / IFAC Proceedings series. - Kildington : Elsevier. - 1474-6670. ; 32:2, s. 6998-7003, s. 391-396 Journal article (peer-reviewed)abstract The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed
8.	Fischer, Britta, et al. (author) Control Relevant Identification in H∞ - Adaptive Information and Experiment Design 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429084 ; 29:1, s. 4046-4051 Journal article (peer-reviewed)abstract Joint issues of modelling and control design are studied in a frequency domain setup. Stable systems with monotone Bode plots are chosen as the basis of the study presented in this work. Such dynamics is typical for plants in industrial process control. Adaptive information is considered and both open-loop and closed-loop experimental conditions are included. For systems with monotone Bode plots the information typically required for successful control design consists of a small part of the frequency response only. This can be exploited in experiment design.
9.	Fischer, Britta, et al. (author) Laguerre domain estimation of time delays in narrowband ultrasonic echoes 1999 In: Proceedings of the 14th World Congress. - Kildington : Publ. for the International Federation of Automatic Control by Pergamon. - 1474-6670. - 0080432190 ; , s. 361-366 Conference paper (peer-reviewed)abstract The time delay of arrival (TDOA) is required in many areas in signal processing. In this paper we propose a novel and straightforward method to estimate small continuous time delays in narrowband signals out of a sampled sequence of the input and output signals. It is based on the parameterization of the identification problem in the Laguerre functions. An lp norm optimal estimator is then applied to estimate the delay. Furthermore, estimation bounds are studied and experiments from ultrasonic applications are presented to highlight the performance of the method
10.	Forsberg, Johan, et al. (author) An autonomous plastering robot for walls and ceilings 1995 In: Elsevier IFAC Publications / IFAC Proceedings series. - Oxford : Pergamon Press. - 1474-6670. - 0080423663 ; 28:11, s. 301-306 Journal article (peer-reviewed)abstract This paper presents a robot and algorithms for autonomous spray plastering of walls and ceilings during the construction of apartment houses. Successful experimental tests are described where the robot measures the size of the room and the location of doors and windows. The work sequence is then planned and executed autonomously. To sense the environment the robot uses a range measuring scanning laser. The range weighted Hough transform is used to observe the walls and the resulting observations are used to update estimates in an extended Kalman filter based map. Association of observations to estimates is performed using the estimated probability of a correct match, taking correlations between estimates into account when needed.
11.	Hillerström, Gunnar, et al. (author) Repetitive control theory and applications : a survey 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429084 ; 29:1, s. 1446-1451 Journal article (peer-reviewed)abstract The aim of this paper is to present repetitive control, controllers for rejecting periodic disturbances or tracking periodic reference signals, This survey covers both continuous and discrete time theory, together with a number of applications
12.	Högström, Tomas, et al. (author) On Segmentation, Shape Estimation and Navigation Using 3D Laser Range Measurements of Forest Scenes 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080429297 ; 31:3, s. 423-428 Journal article (peer-reviewed)abstract The problem addressed is segmentation and shape estimation of three-dimensional laser range measurements of forest scenes. For each tree the position as well as the three dimensional shape of the trunk is estimated. The detection uses a two-dimensional histogram of the measurements, followed by segmentation by fitting cylinders around the measurements of each detected tree trunk. The shape estimation consists of fitting a 3D spline to each tree trunk's centre curve and computing the trunk width by extracting the range discontinuities at the edges. For the experiments a mobile robot carrying a scanning laser range finder was used. Navigation was done by matching the extracted tree trunk positions from subsequent range scans, determining the relative movements
13.	Högström, Tomas, et al. (author) Telecommands for Remotely Operated Vehicles 1995 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080423663 ; 28:11, s. 301-306 Journal article (peer-reviewed)abstract The problem addressed is controlling a robot over a communication channel with low bandwidth, a non-neglectable time delay and time jitters. The external sensors on the robot are a time-of-flight range measuring laser and a video camera. Video images are used by the operator for interpreting the scene and are only sent at “fax rate”. The operator is thus interpreting the workspace around the vehicle, making plans for the individual operations in a composite task and is giving high level commands. The telecommands are to be executed autonomously by the robot. Inside the robot the control loop is closed with full bandwidth when each command is executed.This paper reports on work in progress and focus on:1. Incremental map building, especially simplifications for large buildings and robustness when the vehicle returns to a previously mapped area. This is a very useful support function for the operator.2. Tests of telecommands on a mobile robot available for experiments over the Internet. Available sensors are inclinometers, odometry, CCD intensity images and range measuring laser data.Other needed telecommands studied previously are:Travelling along corridors, follow walls etc. The operation is based on the range weighted Hough transform and is both robust and precise. The repeatability is about 1 cm at 1 m/s. The robot is not disturbed by people passing in the corridor.Commands for passage through an open door works within 1 cm and 0.5 degrees at a speed of 0.5 m/s. Passing between irregular obstacles is less accurate.Using rate gyros, lock the heading of the robot when driving on a straight line. Also preprogrammed 90- and 180-degrees turns.Automatically enter a camera defined line. The direction of the camera can be used to drop a new coordinate frame at any time (using a button on the keyboard). The robot will automatically enter this new line and also compensate for the overshoot.To integrate these different commands into a complete system is a resource demanding task for the future.
14.	Johansson, Andreas, et al. (author) Nonlinear observer for estimation of metal analysis in steel converters 2001 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080435602 ; 34:6, s. 1325-1330 Journal article (peer-reviewed)abstract A nonlinear observer whose feedback is weighted by the sensitivity of the output with respect to the state is considered. Conditions for asymptotic stability as well as a region of attraction of the estimation error equation are derived. The results are applied to the problem of metal analysis estimation in a steel converter process
15.	Larsson, Ulf, et al. (author) On rate gyros for improved navigation by reducing dead-reckoning errors 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - Oxford : Pergamon Press. - 1474-6670. ; 31:3, s. 207-212, s. 207-212 Journal article (peer-reviewed)abstract Consider a vehicle using a number of landmarks for navigation. Between the observation of the landmarks, the motion of the vehicle is estimated using internal sensors like odometers and rate gyros. The output from a dead reckoning algorithm is used in a Kalman filter and/or used to make association of observed landmarks. In such a system the accuracy of the dead reckoning algorithm is essential for the overall performance. In the paper `slip angles' at the wheel-surface contact point are included in the kinematic model. The slip angle is assumed to be essentially proportional to the side force. The topics considered in the paper are: dead reckoning model with a slip angle; improved dead reckoning when a rate gyro is used; and equations for comparing the error growth. Four different algorithms for dead reckoning are studied and compared. Two of them just model the slippage and two of them are based on more accurate measurements of rotation, using a rate gyro
16.	Madala, Hemarao (author) GMDH as an identification and modelling tool for biotechnical processes 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080299784 ; 16:14, s. 225-229 Journal article (peer-reviewed)abstract This paper describes GMDH as an identification and modelling tool for biotechnical processes. Several examples are considered by using a known simulated data. The identified models could be used further in analysing the processes by using online algorithms.
17.	Madala, Hermano (author) Self-Organization GMDH Computer Aided Design for Modelling of Cyclic Processes 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 16:19, s. 611-618 Journal article (peer-reviewed)abstract The Group Method Data Handling (GMDH) is a specific selforganization computer-aided design which has been proposed by Ivakhnenko (1970, 1971) and which has been described in several recent articles (Ivakhnenko et al, 1978, 1979a) and also in Soviet Automatic Control (USA). One of the several interesting properties of this CAD is its apparent ability to make high accuracy predictions of future states of complex systems. The development presents a procedure for constructing models in a simple and systematic way for complex systems which are cyclic in nature. In the present paper the structures of finite-difference models for cyclic processes are described. The criterion of prediction balance is used for analysing the optimal model. System of combined models constructed in this manner is used recursively for predicting the future states of the cyclic system. Three examples are given. One example used the data generated from a known model and the others the airtemperature data with large number of points and the tea-crop production data with less number of points. The system of combined models is compared with the single overall model. The former has given reasonably better results. The models are checked for stability in long-range actions.
18.	Madala, Hemarao, et al. (author) Some Experimental Results of Digital Signal Processing 1983 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 16:15, s. 531-535 Journal article (peer-reviewed)abstract This paper describes some of the experimental results in processing of signals in finding out the length of a tube. The paper is divided into two parts consisting of different results. The aim of the first part is to find out the behaviour of A parameters of AR model and how they change as the length of the tube varies and to discover a single model of length as a function of A parameters treating the system as a black box. Linear Moving Averages (LMA) used in this paper eased the situation in filtering out the disturbances on A parameters and in getting the exact model. Optimal length of LMA is found out for the given situation. This type of model is useful in the continuous case. In the second part a new harmonical algorithm is described for identifying the signals from the experiment. The estimated models show reasonably good results. The results are discussed for different lengths of the tube.
19.	Medvedev, Alexander (author) Disturbance attenuation in finite spectrum assignment controllers 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier. - 1474-6670. ; 29:1, s. 1620-1625 Journal article (peer-reviewed)abstract Two finite-spectrum-assignment controllers for continuous linear dynamic systems with multiple time delays in input signal are introduced. The controllers are shown to comprise least-squares state estimators. Disturbance attenuation properties stipulated by the choice of shift operator in the observers are studied.
20.	Medvedev, Alexander, et al. (author) External model control of a peristaltic pump 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422292 ; 27:2, s. 519-524 Journal article (peer-reviewed)abstract An observer-based approach to perfect disturbance rejection in linear continuous systems with delayed control is presented and exemplified by an application to a peristaltic pump. Disturbance rejection properties of the Smith Predictor are studied. A recently developed technique of continuous deadbeat observation is exploited to predict the disturbance signal which is described by a known dynamic model. It is shown that under certain algebraic conditions a disturbance estimate based control law is able to provide a disturbance-free output signal. The disturbance rejection scheme can be used in combination with any conventional control technique such as stabilizing or servo controller.
21.	Medvedev, Alexander (author) Fault Detection by Continuous Dead-Beat Observation 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080422225 ; 27:5, s. 28-33 Journal article (peer-reviewed)abstract An application of continuous-time deadbeat observation to fault analysis in linear dynamic systems is discussed. A finite memory residual chosen as a difference of two deadbeat state vector estimates is shown to be independent of both the state vector and control signal. The mapping of the fault mode to the residual is proven to be intrinsically BIBO-stable. Exploiting a decomposition of the “sliding-window” convolution operator, an upper bound for residual norm is derived and a fault detectability condition is obtained. Due to its simple structure, the deadbeat observer does not create a hard computational burden and can be easily implemented in real-time applications.
22.	Medvedev, Alexander (author) State estimation and fault detection by a bank of continuous finite-memory filters 1996 In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier. - 1474-6670. ; 29:1, s. 6542-6547 Journal article (peer-reviewed)abstract A continuous observer estimating the state vector of a linear time-invariant system from the measurements of the system's inputs and outputs passed through a bank of finite-memory filters is introduced. System observability is shown to guarantee the existence of the observer. An application of the observer to the problem of detecting and isolating sensor and actuator faults is discussed
23.	Mäkilä, Pertti, et al. (author) Robust identification 1994 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 27:8, s. 45-63 Journal article (peer-reviewed)abstract This paper introduces the reader to several recent developments in robust identification motivated by various issues of modelling of systems from data for the purpose of robust control design. Many aspects of identification in H∞ and l1 are covered; including algorithms, convergence and divergence results, control relevancy issues, and objective worst case estimation of uncertainty models
24.	Nilsson, Bernt, et al. (author) On Control of Flexible Mobile Manipulators: Positioning and Vibration Reduction Using an Eye-in-Hand Range Camera 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 31:3, s. 619-625 Journal article (peer-reviewed)
25.	Rönnbäck, Stefan, et al. (author) A design algorithm for anti-windup compensators : polynomial approach 1993 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 008042211X ; 26:2:5, s. 619-624 Journal article (peer-reviewed)abstract It is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllersIt is discussed how an LTI ‘polynomial controller’ for a SISO-system with actuator constraints can be designed using conventional linear pole-placement technique. This becomes possible due to the utilization of an ‘anti-windup’ technique in which the effect of control-signal saturation is interpreted as being caused by an equivalent disturbance. The results are summarized into a ‘design algorithm’ which supports a complete separation of 'servo', ‘disturbance-rejection’ and ‘anti-windup’ poles. It also supports the introduction of arbitrary 'specific factors’ into the controller polynomials, and it can be used for both continuous-time and discrete-time controllers.
26.	Rönnbäck, Sven, et al. (author) A Matlab/Java interface to the MICA wheelchair 2004 In: Elsevier IFAC Publications / IFAC Proceedings series. - Kildington : Elsevier. - 1474-6670. - 0080441718 ; 37:7, s. 93-98 Journal article (peer-reviewed)abstract In the MICA (Mobile Internet Connected Assistant) project a high tech wheelchair has been controlled remotely with MATLAB/Java software client-server implementations. Sensor servers that read, time stamp and store sensor device measurements to databases, runs concurrently on an embedded PC running Linux.The network clients used to read sensor values from the servers are written in Java. That gives them portability between different platforms and architectures.MATLAB client programs runs on stationary computers. These are used to process andvisualize collected data from the wheelchair. MATLAB programs are also used to control and make the wheelchair run semi-autonomously.The combination of MATLAB/Java software is good for fast development, implementation and testing of algorithms in both education and research.With the client/server approach it is possible to have one computer to run a complex and power consuming control algorithm and another one to handle the GUI. Both computers execute MATLAB programs and they run concurrently and have mutual exchange of data over the Internet.When a program works properly in MATLAB it can be ported to Java for faster execution speed and portability.
27.	Sololov, Bods M., et al. (author) The Control of the Top Blown Oxygen Converter Process 2001 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080435602 ; 34:6, s. 1331-1335 Journal article (peer-reviewed)abstract This paper considers the control of the top blown oxygen converter process by exploiting the static equations of the process in order to compensate for measured disturbances. The dissipation region of the controller is evaluated. A nonlinear observer is introduced for estimating the metal analysis in real time. It is shown that the observer is asymptotically stable and a region of attraction, where the estimation error converges, is derived
28.	Stenlund, Benny, et al. (author) Level control of cascade coupled flotation tanks 2002 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 33:22, s. 185-190 Journal article (peer-reviewed)abstract At the Boliden's concentrator in Aitik, bulk flotation constitutes an important part of the process for extracting valuable minerals from the ore. A series of flotation cells consists of five tanks connected in cascade with control valves between the tanks and a slowly varying flow of mineral slurry into the first tank. This paper deals with a comparative study of control strategies for level control in a flotation series in Aitik. The aim is to show the potential performance improvements taking into account couplings between the process state variables. Two control strategies are considered; a decoupling controller and a linear quadratic (LQ) optimal multivariable controller. Experiments with both structures show a significant enhancement of the level control performance as compared to the original SISO design
29.	Stenlund, Benny (author) Supervision of Control Valves in a Series of Cascade Coupled Flotation Tanks 2001 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 34:27, s. 57-62 Journal article (peer-reviewed)abstract In this paper an algorithm for supervision of control valves in a series of cascade coupled flotation tanks is presented. The benefit of such an algorithm is that it enables monitoring of the plant control system performance and detection of malfunctions in the control valves at an early stage.
30.	Tano, Kent T., et al. (author) Feature Extraction of a Strain-Gauge Signal Using Wavelets for Monitoring of a Tumbling Mill 2004 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 37:15, s. 35-39 Journal article (peer-reviewed)abstract Techniques that measure the force acting on a lifter bar, when it hits the charge inside a tumbling mill, have got an increased interest because of its direct physical relation to the behavior of the grinding charge. The possibility to combine it with discrete element modeling (DEM), which gives an opportunity to visualize the charge motion, opens new possibilities to understand the complex phenomena that takes place inside a grinding mill. In this work, a method for the measurement of the apparent filling level in a pilot ball mill, the Metso Continuous Charge Measurement system (CCM) has been used. The technique uses a strain gauge sensor, mounted on a flat steel spring, which is fitted into a recess underneath a lifter bar. Deflection of the lifter bar during every mill revolution will then give rise to a characteristic signal pattern depending on different operating conditions.In this work, which should be treated as an introduction, we show how the discrete wavelet transform can be used in multivariate calibration. It will be shown that by using the fast wavelet transform on individual signals as a pre-processing method in regression modeling on CCM measurements, good compression is achieved with almost no loss of information. The predictive ability and diagnostics of the data compressed regression model is almost the same as for the uncompressed.
31.	Ujvari, Sandor, 1972-, et al. (author) Using simulation for the design of Semi-Autonomous Vehicle systems 2001 In: IFAC Proceedings Volumes. - : Elsevier. - 1474-6670. - 0080435548 ; 33:20, s. 351-356 Journal article (peer-reviewed)abstract The paper describes the development of Semi-Autonomous Vehicles (SAVS) in the context of Automated Guided Vehicle Systems (AGVS). During the design process of a complete material handling AGV-system many variables must be decided. A two-stage simulation approach of discrete event simulation and continuous path simulation, improves development and testing of SAVS, Decisions need to be made e. g. what main navigation sensor to use, how many vehicles are needed for the task. The interrelation of these parameters makes it difficult to find optimum or near-optimum values. Because of this, simulation is a very useful tool to design and evaluate AGV-systems. Copyright (C) 2000 IFAC.
32.	Wernersson, Åke (author) Telerobotics : Towards Extending Your Sensing and Hands into a Remote Reality 2004 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 37:7, s. 1-4 Journal article (peer-reviewed)abstract The problem addressed is control of robots and/or sensing, in workspaces at remote locations. Topics taken up in this plenary talk includes laser sensing, scene interpretation, telecommands for local autonomy, research issues especially for multirobot systems. Applications includes aerospace testing in north Sweden.Telecommands are studied for high level control of robots over a communication channel with a non-neglectable time delay, time jitters and variable bandwidth. The sensors onboard the robot are a time-of-flight range measuring laser and a video camera. A few images are used by the operator for interpreting the scene. From the interpretations of the workspace around the robot, the operator specifies interactively the sequence of individual operations during a composite task. Each telecommand is then executed autonomously by closing the feedback loop between the robot and the objects in the surrounding workspace.
33.	Widlund, Daniel, et al. (author) Towards Model-Based Closed-Loop Control of the Basic Oxygen Steelmaking Process 1998 In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 31:23, s. 69-74 Journal article (peer-reviewed)abstract Model-based closed-loop control of the basic oxygen steelmaking process will give an opportunity to increase process operation performance. By using control algorithms that interact with thermodynamical and physical models capable of making real-time predictions of the effects of control actions, the time delays in order to wait for process response will be eliminated. Existing limitations like pre-set lance programs can be avoided. This paper outlines the concept of a recently started project aiming at model-based closed-loop control as well as present the initial work that has been made on the subject.
34.	Alexandre, Seuret, et al. (author) Consensus of Double Integrator Multi-agents under Communication Delay 2009 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. ; , s. 376-381 Conference paper (peer-reviewed)abstract This paper deals with the consensus problem under network induced communication delays. It is well-known that introducing a delay generally leads to a reduce of the performance or to instability. Thus, investigating the impact of time-delays in the consensus problem is an important issue. Another important issue is to obtain an estimate of the convergence rate, which is not straightforward when delays appear in the network. In this paper, the agents are modelled as double integrator systems. It is assumed that each agent receives instantaneously its own output information but receives the information from its neighbors after a constant delay. A stability criterion is provided based on Lyapunov-Krasovskii techniques and is expressed in terms of LMI. An expression of the consensus equilibrium which depends on the delay and on the initial conditions taken in an interval is derived. The results are supported through several simulations for different network symmetric communication schemes.
35.	Andersson, Ingemar, 1969, et al. (author) Detection of Combustion Properties in a Diesel Engine using Block Mounted Accelerometers 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 11866-11871 Conference paper (peer-reviewed)abstract Engine block mounted accelerometers was used for estimating combustion phasing parameters for a heavy duty diesel engine. Several sensor locations were evaluated for its sensitivity to combustion related vibrations and mechanical noise.One sensor-cylinder combination was selected for the evaluation of a simple algorithm to detect 10% and 50% burned mass fraction. The algorithm uses the accumulated accelerometer vibration energy as a base for extracting the 10% and 50% points respectively.The results show that the angular positions for 10% and 50% burned mass fraction can be estimated with precisions of 1.5 and 3 CAD respectively. It is also concluded that the early part of the accelerometer signal has a significant influence from a mechanical noise source related to the start of injection.
36.	Andreasson, Sven Arne, 1949 (author) A Recursive Framework for Manufacturing Control 2009 In: 13th IFAC Symposium on Information Control Problems in Manufacturing, INCOM'09; Moscow; Russian Federation; 3 June 2009 through 5 June 2009. - 1474-6670. - 9783902661432 ; 13:1, s. 600-605 Conference paper (peer-reviewed)abstract The CHAMP (Chalmers Architecture and Methodology for Flexible Production) system is a general control system for manufacturing that can be configured for arbitrary production. The same system can be used recursive at different levels of the production. The system consists of producers that can perform operations on products and movers that can move products between producers. Each product is described by a number of operations that are mapped to global operations in the database. Thus a flexible production can be designed only by defining the product recipes and the factory layout.
37.	Anguelova, Milena, 1978, et al. (author) An Efficient Method for Structural Identiability Analysis of Large Dynamic Systems 2012 In: 16th IFAC Symposium on System Identification. - 1474-6670. - 9783902823069 ; 16:1, s. 941-946 Conference paper (peer-reviewed)abstract Ordinary differential equation models often contain a large number of parameters that must be determined from measurements by parameter estimation. For a parameter estimation procedure to be successful, there must be a unique set of parameters that can have produced the measured data. This is not the case if a model is not structurally identifiable with the given set of outputs selected as measurements. We describe the implementation of a recent probabilistic semi-numerical method for testing local structural identifiability based on computing the rank of a numerically instantiated Jacobian matrix (observability/identifiability matrix). To obtain this, matrix parameters and initial conditions are specialized to random integer numbers, inputs are specialized to truncated random integer coefficient power series, and the corresponding output of the state space system is computed in terms of a truncated power series, which then is utilized to calculate the elements of a Jacobian matrix. To reduce the memory requirements and increase the speed of the computations all operations are done modulo a large prime number. The method has been extended to handle parametrized initial conditions and is demonstrated to be capable of handling systems in the order of a hundred state variables and equally many parameters on a standard desktop computer.
38.	Anguelova, Milena, 1978, et al. (author) When classical nonlinear time-delay state-space systems admit an input-output equation of neutral type 2010 In: 9th IFAC Workshop on Time Delay Systems, TDS 2010, Prague, 7 - 9 June 2010. - 1474-6670. - 9783902661715 ; 9:PART 1, s. 200-205 Conference paper (peer-reviewed)abstract This paper deals with nonlinear retarded time-delay systems that surprisingly admit an input-output representation of neutral type. It is shown that such an unexpected behaviour represents a strictly nonlinear phenomenon, for it cannot happen in the linear time-delay case where retarded systems always admit an input-output representation of retarded type. A necessary and sufficient condition under which the nonlinear systems admit a neutral input-output representation is given and strategies for finding an inputoutput representation of retarded type are briefly outlined. Some open problems that arise, like minimality and system transformations, are discussed as well.
39.	Barata, José, et al. (author) Evolvable Assembly Systems : A Development Roadmap 2006 In: IFAC Proceedings Volumes. - : Elsevier BV. - 1474-6670. - 9783902661043 Conference paper (peer-reviewed)abstract A new paradigm, the Evolvable Assembly Systems (EAS), was recently proposed. This paradigm provides a complete new view on how assembly systems should be designed and developed. Because the control system is one of the key aspects for a successful implementation of EAS this paper proposes a development roadmap to pinpoint directions of research on how control systems should be developed. It is expected that with this information the industry can envision the potential benefits in terms of competitiveness of this approach; still, this paper is especially targeted to motivate researchers from self-organisation and distributed assembly systems to engage in this endeavour together. In particular, topics on self-organisation, emergence, dynamical systems, and distributed artificial intelligence can be the backbone of truly self-adapting assembly systems. In fact EAS seems to be a really demanding and grounded case-study for the referred research communities.
40.	Barcellini, Alberto, et al. (author) Integrating an Anti-Collision System Based on Laser Time-Of-Flight Sensor in an Industrial Robot Controller 2012 In: 10th IFAC Symposium on Robot Control. - 1474-6670. - 9783902823113 ; , s. 664-669 Conference paper (peer-reviewed)abstract Safe coexistence of industrial robots and human operators in the same workspace is one of the long standing goals of robotics research. One way to enforce safety is to endow the robotic system with additional sensors that can to some extent monitor the environment surrounding the robot and allow fast reaction to unexpected obstacles. This paper discusses the design of one such anti-collision system based on a laser Time-Of-Flight distance sensor. Integration of the external controller in the hardware and software architecture of a commercial industrial robot controller is discussed. Experimental results show fast response of the system to various obstacles
41.	Bengtsson, Kristofer, 1979, et al. (author) Aspect-Oriented Programming for Manufacturing Automation Control Systems 2009 In: 13th IFAC Symposium on Information Control Problems in Manufacturing Technology, INCOM’09, Moscow, Russia. - 1474-6670. - 9783902661432 ; :PART 1, s. 668-673 Conference paper (peer-reviewed)abstract The languages defined by the standard IEC 6-1131 for Programm\-able Logic Controllers (PLCs), have both benefits and drawbacks compared to object-oriented programming languages. For example, the current programming approach is good for maintaining the system, since it is easy to program and comprehend for a plant floor personal with limited programming experience. The main drawbacks are reusability, code dependability and flexibility. This paper proposes an aspect-oriented programming (AOP) approach as an alternative solution, which can keep the benefits and eliminate the drawbacks. AOP is an emerging programming methodology in computer science, which helps the programmer by separating different crosscutting concerns in the program. These crosscutting concerns and tangled behavior are especially important issues in PLC programming, which makes AOP a suitable approach. The paper describes how to adapt the AOP methodology into PLC program development and how it can benefit the control design process.
42.	Binotto, Alécio Pedro Delazari, et al. (author) Towards Dynamic Task Scheduling and Reconfiguration using an Aspect Oriented Approach applied on Real-time concerns of Industrial Systems 2009 In: Elsevier IFAC Publications / IFAC Proceedings series. - Frankfurt : Elsevier. - 1474-6670. ; 13:PART 1, s. 1423-1428 Journal article (peer-reviewed)abstract High performance computational platforms are required by industries that make use of automatic methods to manage modern machines, which are mostly controlled by high-performance specific hardware with processing capabilities. It usually works together with CPUs, forming a powerful execution platform. On an industrial production line, distinct tasks can be assigned to be processed by different machines depending on certain conditions and production parameters. However, these conditions can change at run-time influenced mainly by machine failure and maintenance, priorities changes, and possible new better task distribution. Therefore, self-adaptive computing is a potential paradigm as it can provide flexibility to explore the machine resources and improve performance on different execution scenarios of the production line. One approach is to explore scheduling and run-time task migration among machines’ hardware towards a balancing of tasks, aiming performance and production gain. This way, the monitoring of time requirements and its crosscutting behaviour play an important role for task (re)allocation decisions. This paper introduces the use of software aspect-oriented paradigms to perform machines’ monitoring and a self-rescheduling strategy of tasks to address nonfunctional timing constraints. As case study, tasks for a production line of aluminium ingots are designed. © 2009 IFAC.
43.	Björkelund, Anders, et al. (author) Knowledge and Skill Representations for Robotized Production 2011 In: Proceedings of the 18th IFAC World Congress, 2011. - 1474-6670. - 9783902661937 ; , s. 8999-9004 Conference paper (peer-reviewed)abstract Model-based systems in control are a means to utilize efficiently human knowledge and achieve high performance. While models consisting of formalized knowledge are used during the engineering step, running systems usually do not contain a high-level, symbolic representation of the control and most of its properties, typically named numerical parameters. On a system level and beyond the plant data, there is also a need to represent the meaning of the data such that deployment and fault analysis could be augmented with partly automated inference based on the semantics of the data. To that end, we extended the formalized knowledge traditionally used in control to include the control purpose, engineering assumption, quality, involved state machines, and so on. We then represented the control semantics in a format that allows an easier extraction of information using querying and reasoning. It aims at making knowledge in control engineering reusable so that it can be shipped together with the control systems. We implemented prototypes that include automatic conversion of plant data from AutomationML into RDF triples, as well as the automated extraction of control properties, the conversion of parameters, and their storage in the same triple store. Although these techniques are standard within the semantic web community, we believe that our robotic prototypes for semantic control represent a novel approach.
44.	Bonafilia, Brian, et al. (author) Robust manual control of a manufacturing system using supervisory control theory 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 748-753 Conference paper (peer-reviewed)abstract There are many situations where manual intervention in automated systems, such as flexible manufacturing systems, is inevitable. Commonly the control of a manufacturing system is implemented in terms of operations, and sequences thereof, and these operations can typically be run manually. However, running the operations in arbitrary order may lead to situations such as blocking or collisions, from which it its hard or even impossible to recover or to resume automatic execution. This paper describes an implementation of an operator interface for robust manual control of a manufacturing system, where the operator is aided not to manually drive the system into a state that breaches the system requirements. Hence, blocking and collisions are avoided, and automatic mode can always be resumed. From a model of the manufacturing system based on self-contained operations, each of which is identified in terms of events with preconditions, a supervisor is calculated by use of the Supervisory Control Theory framework. From this supervisor additional preconditions are extracted for each operation. The operations with the extended preconditions are then ported to an operator interface which allows manual control of the production cell by dynamically guiding the operator to only those operations for which the extended preconditions are satisfied.
45.	Boström, Mathias, et al. (author) Ion specific forces between charged self-assembled monolayersexplained by modified DLVO theory 2009 In: Elsevier IFAC Publications / IFAC Proceedings series. - : Elsevier BV. - 1474-6670. ; 346:1-3, s. 11-15 Journal article (peer-reviewed)abstract We recently investigated specific ion effects near a single charged self-assembled monolayer (SAM) in asalt solution by exploiting a modified Poisson–Boltzmann equation that accounts for both water profileand ion-surface potential profiles inferred from molecular dynamics simulations. In the present contributionwe extend this work to consider two charged SAMs interacting across different salt solution. Ourresults demonstrate one important reason why the double layer force between charged colloidal surfacesin electrolytes could be highly ion specific.
46.	Bottegal, Giulio, et al. (author) Analysis and identification of complex stochastic systems admitting a flocking structure 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 1474-6670. - 9783902823625 ; , s. 2323-2328 Conference paper (peer-reviewed)abstract We discuss a new modeling paradigm for large dimensional aggregates of stochastic systems by Generalized Factor Analysis (GFA) models. These models describe the data as the sum of a flocking plus an uncorrelated idiosyncratic component. The flocking component describes a sort of collective orderly motion which admits a much simpler mathematical description than the whole ensemble while the idiosyncratic component describes weakly correlated noise. The extraction of the dynamic flocking component is discussed for time-stationary systems.
47.	Cescon, Marzia, et al. (author) On Data-driven Multistep Subspace-based Linear Predictors 2011 In: 18th IFAC World Congress. - 1474-6670. - 9783902661937 ; 44:1, s. 11447-11452 Conference paper (peer-reviewed)abstract The focus of this contribution is the estimation of multi-step-ahead linear multivariate predictors of the output making use of finite input-output data sequences. Different strategies will be presented, the common factor being the exploitations of geometric operations on appropriate subspaces spanned by the data. In order to test the capabilities of the proposed methods in predicting new data, a real-life example, namely, the case of blood glucose prediction in Type 1 Diabetes patients, is provided.
48.	Cho, Jang Ho, et al. (author) On the H2 Decentralized Controller Synthesis for Delayed Bilateral Teleoperation Systems 2012 In: 10th IFAC Symposium on Robot Control. - 1474-6670. - 9783902823113 ; , s. 393-398 Conference paper (peer-reviewed)abstract Procedure for the synthesis of decentralized controllers for delayed bilateral teleoperation systems is proposed, based on the analytical solution of a global H2 optimization. Explicit state-space formulae for the optimal controller are presented. The controller possesses a neat structure, which preserves closed-loop stability regardless of the delay length. The behavior of the resulting teleoperation system is illustrated in simulations and verified by experiments.
49.	Dabiri, Azita, 1984, et al. (author) Incident parameter scheduled freeway traffic control - A ramp meter approach 2014 In: IFAC Proceedings Volumes (IFAC-PapersOnline). - : Elsevier BV. - 2405-8963 .- 1474-6670. - 9783902823625 ; 19, s. 11338-11343 Conference paper (peer-reviewed)abstract A novel model based local ramp metering method is presented in the paper by means of incident scheduled freeway traffic control solution. First, second order macroscopic freeway model is used with appropriate incident parametrization to describe eventual and unattended traffic variation caused by off-nominal traffic conditions (e.g. accidents). These traffic anomalies are captured by adequate model parameters, i.e. incident parameters that can be on-line estimated. The paper is motivated by incident scheduled ramp-meter solution to encounter real-time incident parameter information. The main idea is to use local freeway control solution triggered by available incident parameter values. The proposed approach is local in the sense of considering only non-coordinated ramp meter solution, first. Furthermore, we apply locally optimal (linearized) control solution to satisfy throughput maximization objective. The formal controller synthesis involves parameters to correct, compensate the effect of incidents. The proposed method is evaluated and compared to other existing approach by using simulation environment.
50.	Deng, Qichen, et al. (author) A fast algorithm for planning optimal platoon speeds on highway 2014 In: Elsevier IFAC Publications / IFAC Proceedings series. - : IFAC Papers Online. - 1474-6670. - 9783902823625 ; 19, s. 8073-8078 Journal article (peer-reviewed)abstract To meet policy requirements on increased transport energy efficiency and reduced emissions, smart control and management of vehicles and fleets have become important for the development of eco-friendly intelligent transportation systems (ITS). The emergence of new information and communication technologies and their applications, particularly vehicle-to-vehicle and vehicle-to-infrastructure communication, facilitates the implementation of autonomous vehicle concepts, and meanwhile serves as an effective means for control of vehicle fleet by continuously providing support and guidance to drivers. While convoy driving of trucks by longitudinal automation could save 5-15% of fuel consumption due to the reduction of airdrag resistance, this study attempts to investigate the energy saving potential of truck platoons by intelligent speed planning. Assuming that real-time traffic information is available because of communication, an efficient speed control algorithm is proposed based on optimal control theory. The method is faster than the conventional dynamic programming approach and hence applied in the study to analyze energy saving potential of simple platoon operations including acceleration and deceleration. The numerical result shows significant improvement on energy saving due to speed planning during platooning. It can be further applied for more complex platooning operations.

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